Atmospheric concentrations and temporal trends of polychlorinated biphenyls and organochlorine pesticides in the Arctic during 2011-2018

Passive air samples were deployed in Ny-Alesund and London Island (Svalbard, High Arctic) annually for seven years (2011-2018) to investigate concentrations, temporal trends and potential sources of selected persistent organic pollutants (POPs). Nine polychlorinated biphenyls and twelve organochlorine pesticides were detected in all samples, with 3,3'-dichlorobiphenyl (PCB-11) being the prevalent congener. Concentrations of most compounds were declining. The ratio of the alpha- and gamma-isomer of hexachlorocyclohexane (HCH) in Arctic air was comparable with that in technical HCH mixtures, but higher than that in the atmosphere of other countries, thereby indicating the impact of historical use as well as the possible photoisomerization of the gamma- into the alpha-isomer. The parent dichlorodiphenyltrichloroethane (DDT) was always less abundant than its degradation products dichlorodiphenylethylene (DDE), indicative of the impact of aged DDT sources in the Arctic atmosphere. However, o,p'-/p,p'-DDT ratios suggest only a minor contribution of dicofol-type DDT. A slightly declining temporal trend of the trans-chlordane/cis-chlordane ratio indicated the impact of secondary sources. The atmospheric distribution of the investigated POPs in the Arctic was mainly attributed to long-range atmospheric transport, whereas the influence of human activities from the scientific research stations was minor. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

Passive air samples were collected in Ny-Alesund and London Island in the Arctic annually for seven years to investigate concentrations of persistent organic pollutants (POPs). The study found declining trends in most POPs, with 3,3'-dichlorobiphenyl (PCB-11) being prevalent. Long-range atmospheric transport was identified as the main factor influencing the distribution of POPs in the Arctic atmosphere, with minor impact from human activities at research stations.